Like many countries, Japan uses a 12-month calendar. The names are very simple. January is literally “Month One”, February is “Month Two”, etc:
一月 = January
二月 = February
However, before the Meiji Restoration (mid-1800s) it was common to use an older 12-month system. These months’ names referenced the weather and the seasons (similar to the French Revolutionary calendar).
July is 文月.
文 refers to text, letters or characters. (As in 文字 “letter/character”.)
So what does July have to do with writing?
On July 7th is the Japanese festival of 七夕 tanabata, also known as “the Star Festival”. This festival is famously celebrated by writing one’s wish on a piece of paper and tying it to a bamboo plant. You can see these bamboo plants covered in colourful paper wishes all over Japan at this time.